Consilience powers the big scientific ideas

Science is not a democracy. But as Paul Willis explains, the consilience of evidence for theories such as evolution, and that of anthropogenic climate change area what give the big theories their power.

Transcript

Robyn Williams: What do you think of these statements: 'most scientists link high cholesterol with heart disease', or 'there is a consensus that marijuana use can lead to psychosis in teenagers', or 'most astronomers believe life came to Earth from outer space'? Anything wrong? Well, here's Dr Paul Willis, director of the RiAus in Adelaide.

Paul Willis: Science is not a democracy. A consensus of evidence may be interesting but technically it may not be significant. The thoughts of a majority of scientists doesn't mean a hill of beans. It's all about the evidence. And science is never settled. These are refrains that I and other science communicators have been using over and over again when we turn to analysing debates and discussions based on scientific principles. I think we get torn between remaining true to the philosophical principles by which science is conducted and trying to make those principles familiar to an audience that probably does not understand them.

So let me introduce a concept that is all too often overlooked that can actually explain the anatomy of a scientific debate. It's the phonically beautiful term 'consilience'. Consilience means to use several different lines of inquiry that converge on the same or similar conclusions. The more independent investigations you have that reach the same result, the more confidence you can have that the conclusion is correct. Moreover, if one independent investigation produces a result that is at odds with the consilience of several other investigations, that is an indication that the error is probably in the methods of the adherent investigation, not in the conclusions of the consilience.

Let's take an example to unpack this concept, an example where I first came across the term, and it's a beautiful case of consilience at work. Charles Darwin's On the Origin of Species is a masterpiece of consilience. Each chapter is a separate line of investigation and within each chapter there are numerous examples, investigations and experiments that all join together to reach the same conclusion; that life changes through time and that life has evolved on Earth.

Take apart On the Origin of Species case by case and no single piece of evidence that Darwin mustered conclusively demonstrates that evolution is true. But add those cases back together and the consilience is clear; evidence from artificial breeding, palaeontology, comparative morphology and a host of other independent lines of investigation combine to confirm the same inescapable conclusion.

That was 1859. Since then yet more investigations have been added to the consilience for evolution. What's more, these investigations within the biological and geological sciences have been joined by others from physics and chemistry, as well as completely new areas of science such as genetics, radiometric dating and molecular biology. Each independent line of investigation builds the consilience that the world and the universe are extremely old and that life has evolved through unfathomable durations of time here on our home planet.

So, when a new line of investigation comes along claiming evidence and conclusions contrary to evolution, how can that be accommodated within the consilience? How does it relate to so many independent strains conjoined by a similar conclusion at odds with the newcomer? Can one piece of evidence overthrow such a huge body of work?

Such is the thinking of those pesky creationists who regularly come up with 'Ah-ha!' and 'Gotcha!' factoids that apparently overturn not just evolution, but the whole consilience of science. Without exception, every single case that has been brought forward over the years does not hold up to scrutiny: the contrary result is in error and thus not really in conflict with the consilience. Depressingly, most of the examples that the creationists put forward have been discredited time and time again but they are always willing to try their hand at foisting discredited material on a new, naive audience.

The same can be said of the climate change debate. While it has been pointed out many times that this is not an even debate and that the vast majority of climate scientists are in one camp, this by itself is not particularly helpful. Science is not a democracy. But what has been underplayed is that the consilience of evidence for anthropogenic climate change is particularly strong. The IPCC reports are a consilience of hundreds of independent lines of evidence all converging on the same or similar conclusions. Supplement that body of work with complementary investigations outside of the reports and the consilience builds. We have more confidence that their conclusions are correct. This is then magnified because of the consilience between the investigations within climate change research and the findings of the rest of science. They all point to the same conclusions about how the world works and climate change is comfortably nested within all the other scientific disciplines.

The term 'consilience' and its basic principles were coined by the polymath William Whewell (1794 - 1866). He was truly a remarkable man, partly because of the breadth of his work taking in philosophy, theology, physics, mineralogy, mathematics, poetry, astronomy, economics, mechanics and others. He also coined many other words besides 'consilience' that have entered the scientific and general lexicon. He came up with the word 'scientist' as well as 'physicist', 'catastrophism' and 'uniformitarianism', and he went on to suggest to Michael Faraday words such as 'ion', 'anode', 'cathode' and 'dielectric'.

Among his many notable associations, while he was a don at Cambridge he met a young student called Charles Darwin, and later recommended him for the position of secretary for the Geological Society of London. In honour of their enduring friendship, Darwin quoted Whewell on the frontispiece of On the Origin of Species:

'But with regard to the material world, we can at least go so far as this—we can perceive that events are brought about not by insulated interpositions of Divine power, exerted in each particular case, but by the establishment of general laws.'

And thus was born the origin of the great consilience of human endeavour that we call 'science'.

Robyn Williams: Whewell [Where-well]? When I was at Trinity College in Cambridge in 1833 we called him Whewell [Hew-ell]. That was the year Whewell coined the name 'scientist'. Doctor Who was at that meeting too. Dr Willis is the director of the RiAus in Adelaide.

Guests

Paul Willis

DirectorRi AusAdelaide SA

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Comments (2)

Greg :

28 Nov 2013 1:00:32pm

This presentation concilience does not seem complete or coherent. Based on the material presented, concilience could just as easily be used by barristers or lawyers, who actually use rhetoric, and not necessarily logical argumentation - they seek to produce "preponderance" of evidence to a jury.

The presentation also does not seem to differentiate concilience from the fallacy of Composition. Additionally, and perhaps fatal to the speaker's remarks, in mathematics and logic, if not current scientific practice, a single exception to an hypothesis is sufficient to disprove it.

Perhaps if the time and text spent on the unsupported allegations and generally negative rhetoric about "creationists" was used to substantiate the speaker's remarks, the identified failings could have been avoided.

Marcus Morgan :

07 Dec 2013 12:32:24pm

Dr. Willis should read my free book at http://thehumandesign.net as I provide some weight to alternative interpretations of evolution. Selection as suitability to environment is inevitable if an organism grows within an environment. It's very basic and uninformative beyond a broad inevitable connection. In fact it's not actually predictive, which a science should be, because mutations are supposedly random and they will create unpredictable novelties.

In fact, Selection is just an umbrella principle, or weak hypothesis, not because its only weakly likely to be correct - its strongly likely to be correct - but because it says very little. The correct scientific approach is to consider pre-existing chemical capacities of the environment used to construct anatomies in the first place, and then worry about Selection supporting them by suitable environmental connections.

DNA is just a digital strand encoding construction of cells using environmental chemical. Life is from non-life that exists in pre-existing chemical layers in settled landscapes. DNA uses inorganic chemicals for organic construction, and it constructs in conformity with inorganic chemical capacities on earth's surface. Anatomies may be the literal embodiment of inorganic chemicals of landscapes, and evolution becomes predictive because those chemical layers provide anatomical structures - we are entirely composed of them - DNA is just a strand.

You can read more in my book, which provides a complete argument, and relates human awareness to having comprehensive anatomical chemical capacities from inorganic chemical capacities. Our structure has specific capacities suitable for comprehensive awareness.

The lesson for Dr. Willis, is to be more open minded. I am not a creationist, but the inevitable conclusion I reach is that human-type anatomies are the most economical embodiment of earth's range of chemicals in their inorganic layers.

Our anatomical structure has specific capacities ordered as they would be on our planetary surface, and the most economical of any species in that regard. The book is called the Human Design, not because a deity designed us, but because there may be a design to the laws of nature inevitably evolving human-types on earth-type surfaces. A challenge to the hubris of Dr. Willis.